Improvement in slide-valves for steam-engines



MFEYERS, PHO LITHOGRAPHER WASHINGTON D C UNITE STATES PATENT OFFICE.

JOSEPH F. HAMILTON, OF PITTSBURG, PENNSYLVANIA.

lMPROVEMENT IN SLIDE-VALVES FOR. STEAM-ENGINES.

Specification forming part of Letters Patent No. 39,344, dated July 28,1863.

To all whom t may concern:

Be it known that I, Josnrn F. HAMILTON, of Pittsburg, in the county ofAllegheny and State otA Pennsylvania, have invented a new and usefulImprovement for Relieving Slide- Valves from the Pressure of Steam; andI do hereby declare that the followingis a i'ull and exact descriptionthereof, reference beinghad to the accompanying drawings, and to theletters of reference marked thereon.

The nature of my invention consists in the use of inclined planes placedon the sides ot' a steamchest, and grooves in a plate placed over aslide-valve, said inclined planes and grooves being used in connectionwith a metallic compound and a screw for the purpose of tting, setting,and adjusting said plate to the slide-valve, the whole beingconstructed, arranged, and operating in the manner substantially ashereinafter described.

.To enable others skilled in the art to make and use my invention, Iwill proceed to describe its construction and operation.

In the accompanying drawings, Figures l and 2 represent longitudinal andsectional views ot' the ordinary steam-chest and slidevalve, furnishedwith the suspended plate for relieving the valve from the pressure ofthe steam. Fig. 3 is a sectional view ofthe steamchest and slide-valve,and represents the suspended plate drawn up the inclined planes and olfthe valve. Fig. et is a transverse and sectional view of thesteam-chest, slide-valve, and suspended plate. Fig. 5 is a sectionalview of the steanrchest. Fig. 6 is a transverse and sectional view ot'the suspended plate.

In theaccompanying drawings, a represents the steam-chest. brepresentsthe lid of the steam-chest. c represents the suspened plate, the underside of which is planed and dressed true. d represents the slide-valve,the upper and lower faces of which are planed and dressed parallel witheach other. e represents the inclined planes, which arecast on the innersides of the steam-chest. The upper sides of these planes are planed,dressed, and made parallel with each other. f represents a screw usedfor the purpose of moving the suspended plate up and down on theinclined planes e. g represents the valve-stem. h represents thevalveseat. i represents the exhaust-openin g. j represents thesteam-port. 7c represents the cavity in the slide-valve. r representsgrooves in the sides of the suspended plate. These. grooves are madewider than the inclined planes e, for the purpose ot' allowing room fora strip of Babbitt metal,77 or other soft metallic compound. t representopenings made in the suspended plate, for purpose of runnin g themetallic compound into the grooves and on the inclined planes. representstrips ot' Babbitt metal or other metallic compound.

The red dotted lines l m a o s represent the following device orarrangement: lrepresents a hollow screw, on the upper end ot' which isplaced an oil cup, m. n represents an oil or steam cock. orepresentsasmallblock or strip of iron, the under side ot' which ishollowed out for the purpose of allowing'the suspended plate to be movedup or down on the inclined planes, and still have the opening s in. theplate c kept in free communication with the hollow screw l, which isfitted to a cavityq Abe oiled, and leakage of steam between the valveand plate may be detected, and it also answers as a means for holdingdown the valve and plate to their place. Having the various parts madeand dressed as herein de scribed, I arrange the valve d on its seat IL.I then place the plate c onv top of the valve, with the inclined planesin the grooves r. ll then run the metallic compound into the grooves andonto the inclined planes through the openings t. Thus, by the use of thegrooves and the metallic compound, the suspended plate is with ease andcertainty tted to the inclined planes and to the top of the valve.Another very great advantage gained by the use of the metallic compoundis overcomingthe difference in the expansion between the plate c andvalve d. The valve being of greater depth or thicker than the plate c.it willof necessity expand more, and will thereby press against theplate and lit't it from its seat on the inclined planes. Now, thisdifficulty can be entirely obviated by the use of some one ot' the knownmetallic compounds. It is a fact well known to mechanics skilled inmetallurgy that many of the soft metallic compounds now in use willexpand more than the metal of which slide-valves are usually made. Now,by ascertaining the difference in the eX- pansion between the two metalsand by making the strips :v in such proportion that their expansion willbe equal to the expansion of the valve, the difculty arising from thedifference in expansion between the valve and plate will be overcome.

The operation of my improvement is as follows: Having all thingsarranged as setforth, with the lid b of the steam chest secured to itsplace, the steam is then conducted into the chest a in the usual manner;but the pressure of the steam, which usually comes on the top of theValve, causing it to press heavily on its seat, is received by thesuspended plate, thereby relieving the valve from pressure and making'it truly a balance slide-valve. The suspended plate c is raised up ottor brought down on the valve by means ot' the screw f and the inclinedplanes e. It will be observed that by turning` the serewj'in onedirection it will lower the plate c on the inclined planes, and byturningit in an opposite direction it will raise it on theplanes. Hencethe plate c is adjusted to the valve simply by turning the screwf.

I wish it to be clearly understood that I do not claim, broadly, the useot' a plate placed over a slide-valve for relieving` it from thepressure of the steam. I am aware that such device has been used forthat purpose; but

What I do claim as of my invention is- The use of the groovesrand'inelined planes e, when used in combination with the plate c,serewf, and a metallic compound, as herein described, and for thepurpose set forth.

JOSEPH F. IIAMlLTON.

Witnesses:

J AMES J. JOHNSTON, ALEXANDER HAYs.

